Fix data race on fctx->vresult in validated()

Move the write to fctx->vresult after LOCK(&fctx->lock).  The field was
being set before acquiring the lock, but dns_resolver_logfetch() reads
it under the same lock from another thread.

diff --git a/lib/dns/resolver.c b/lib/dns/resolver.c
index a708bd0f0b109aba0a041b35b4685487a0fa6a64..bf800ff067ed013e65b44b7a792c7d6b84c47996 100644 (file)
--- a/lib/dns/resolver.c
+++ b/lib/dns/resolver.c
@@ -5626,7 +5626,6 @@ validated(void *arg) {
        addrinfo = valarg->addrinfo;
 
        message = val->message;
-       fctx->vresult = val->result;
 
        FCTXTRACE("received validation completion event");
 
@@ -5634,6 +5633,8 @@ validated(void *arg) {
 
        LOCK(&fctx->lock);
 
+       fctx->vresult = val->result;
+
        ISC_LIST_UNLINK(fctx->validators, val, link);
 
        if (SHUTTINGDOWN(fctx)) {